Vacuum electronics isolation method

ABSTRACT

A vacuum electronics isolation system utilizes an isolation circuit for providing a low voltage for operating a controller and to provide low voltage control signals for operating the vacuum motor to isolate the high voltage power source from the user.

FIELD

The present disclosure relates to vacuum electronics, and moreparticularly to a vacuum electronics isolation method.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may not constitute prior art.

Conventional industrial shop vacuums are employed for both wet and dryusage. However, the electronics for conventional industrial shop vacuumscan be primitive in design.

SUMMARY

The present disclosure provides electronics for an industrial shopvacuum that provides electronic isolation methods which utilize lowvoltage for operating the controller and control signals to therebyisolate the high voltage power source from the user.

Further areas of applicability will become apparent from the descriptionprovided herein. It should be understood that the description andspecific examples are intended for purposes of illustration only and arenot intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

FIG. 1 is a perspective view of an example industrial shop vacuumaccording to the principles of the present disclosure;

FIG. 2 is a schematic diagram of an example industrial shop vacuumaccording to the principles of the present disclosure; and

FIG. 3 is a schematic circuit diagram for the electronic controlsaccording to the principles of the present disclosure.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is notintended to limit the present disclosure, application, or uses. Itshould be understood that throughout the drawings, correspondingreference numerals indicate like or corresponding parts and features.

With reference to FIGS. 1 and 2, an example vacuum 10, according to theprinciples of the present disclosure, will now be described. The vacuum10 may include a canister 12 and a vacuum head 14 that closes thecanister 12. The vacuum head may support a drive motor 16. The drivemotor 16 may support a suction fan 18, which may be provided in a fanchamber 20 of the vacuum head 14. The fan chamber 20 may be in fluidcommunication with an exhaust port 22 and an intake port 24. The intakeport 24 may be covered by a filter assembly 26 situated in a filterhousing 28 of a vacuum head 14.

A motor 16, when powered up, may rotate the suction fan 18 to draw airinto the suction inlet opening 30 and through the canister 12, throughthe filter assembly 26, through the intake port 24 and into the fanchamber 20. The suction fan 18 may push the air in the fan chamber 20through the exhaust port 22 and out of the vacuum 10. A hose 32 can beattached to the inlet opening 30.

The canister 12 can be supported by wheels 34. The wheels 34 can includecaster wheels, or the wheels can alternatively be supported by an axle.

A filter cleaning device 34 is provided including a filter cleaningmotor 36 drivingly connected to a filter cleaning mechanism 38. Thefilter cleaning mechanism 38 can take many forms, and can include aneccentrically driven arm 40 having fingers 42 engaging the filter 26.The filter cleaning device 34 can be driven to traverse across thefilter 26 to cause debris that is stuck to the filter to be loosened upand fall into the canister 12. The arm 40 is connected to an eccentricdrive member 44 which is connected to motor 36 and, when rotated, causesthe arm 40 and fingers 42 to traverse across the surface of the filter26.

With reference to FIG. 3, a schematic diagram of the electronics 50utilized to operate the vacuum 10 will now be described. The electronics50 generally include a power cord 52 extending from the vacuum andadapted for connection with an AC power source 54. In particular, thepower cord 52 can include a plug 56 having a two-prong or three-prongconnection as is known in the art, as is shown in FIG. 2. The power cord52 is connected to a power source circuit 60. An electrical isolationcircuit 62 is provided in communication with the power source circuit 60for providing a low voltage output VCC, as will be described in greaterdetail herein. A microcontroller 64 is provided in communication withthe electrical isolation circuit 62 for receiving a low voltage supplyVCC therefrom. The microcontroller 64 provides control signals to afilter cleaning circuit 66 and a vacuum circuit 68.

A power tool sense circuit 70 is provided in communication with themicrocontroller 64 for providing a signal to the microcontroller 64regarding operation of a power tool that is plugged into an outlet 72that can be disposed on the power tool 10. The outlet 72 can beconnected to the power cord 52 as indicated by nodes L, N. A water sensecircuit 74 is provided in communication with the microcontroller forproviding a signal (“water”) to the microcontroller 64 that the waterlevel in the canister 12 has reached a predetermined level fordeactivating the vacuum source in order to prevent water from beingdrawn into the vacuum filter 26.

A multi position switch such as four position rotary switch 75 can beutilized for providing different activation states of a firstmicro-switch S1 and a second micro-switch S2 for controlling operationof the vacuum motor 16. The switches S1 and S2 are connected toconnectors A, B and A, C, respectively, wherein connectors B and C areconnected to ratio circuits 76, 78, respectively. Connector A providesan input signal to the microcontroller 64 indicative of the activationstate of micro-switch S1 and micro-switch S2 in order to provide fourmodes of operation utilizing the two micro-switches S1 and S2 whileproviding just a single input into the microcontroller 64. Table 1provides a list of the mode selection possibilities of the four positionuser switch 75 with micro-switches S1 and S2 in the different activationstates.

TABLE 1 User Switch Microcontroller Input Position S1 S2 VCC Ratio 1 0 00 * VCC 2 0 1 (⅓) * VCC 3 1 0 (⅘) * VCC 4 1 1 (⅝) * VCC

With each of the four possible activation states of micro-switches S1and S2, the ratio circuit 76, 78 provide different ratio input signalsas a function of the low voltage supply VCC. In particular, by way ofexample as shown in Table 1, when both switch S1 and switch S2 are open,a zero ratio VCC signal is received by the microcontroller 64. Whenswitch S1 is open and switch S2 is closed, a 1/3 ratio VCC signal isprovided. When the switch S1 is closed and switch S2 is open, a 4/5 VCCratio signal is provided, and when both switches S1 and S2 are closed, a5/8 VCC ratio signal is provided to the microcontroller 64. The ratiosare determined by the resistance levels of resistors R17-R20 provided inthe ratio circuits 76, 78. Ratios, number of switches, and number ofresistors can vary for inputs other than 4. With these four inputsignals provided at a single microcontroller input, four user selectablemodes are provided, thereby simplifying the microcontroller input andreducing the cost of the microcontroller.

The four user selectable modes can include position (1) vacuum off,power outlet is off, auto filter clean is off and filter clean pushbutton is off; position (2) vacuum on, power outlet is off, auto filterclean is off and filter clean push button is on; position (3) vacuum on,power outlet off, auto filter clean is on and filter clean push buttonis on; and position (4) (auto mode) vacuum is controlled by outlet, autofilter clean is on and filter clean push button is on. These operationmodes are exemplary and different modes can be enabled and disabled bythe microcontroller 64. Further, more or fewer switch positions can alsobe employed as well as more micro-switches and ratio circuits can alsobe utilized that are activated by the user switch for providing evenfurther distinct operation modes.

A filter clean switch 80 is also provided for providing a signal to themicrocontroller 64 for operating the filter cleaning device viaactivation of the filter cleaning circuit 66. The filter cleaningcircuit 66 includes an opto-coupler 82 which can be activated by a lowvoltage signal from the microcontroller 64. The opto-coupler 82 providesan activation signal to a triac 84. When the gate of the triac 84 isheld active, the triac 84 conducts electricity to the filter cleaningmotor 36 for activating the filter cleaning device 34. The opto-coupler82 requires only a low power input for holding the triac 84 active.Additionally, the triac may be held continuously active for a timeperiod then turned inactive, or pulsed active/inactive for a timerperiod, or the triac may be replaced by an SCR and driven with DC in asimilar manner just described. The auto filter clean mode will turn offthe vacuum for a brief period while the filter cleaning device 34 movesacross the filter pleats. This can occur at predetermined intervalswhile the vacuum is operated continuously and every time the vacuum isturned off. The filter clean push button mode, when activated by userswitch 75 and be pressing the push button 80, will cause the vacuum toturn off for a brief period while the filter cleaning device 34 isoperated to move across the filter pleats.

The microcontroller 64 can also provide a control signal to the vacuumcircuit 68. The vacuum circuit 68 is provided with an opto-coupler 86which receives a low voltage signal from the micro-controller 64. Theopto-coupler 86 can provide an activation voltage to a triac 88 which isheld active by the voltage supplied by the opto-coupler 86 to provideelectricity to the vacuum motor 16. The opto-coupler 86 requires only alow power input for holding the triac 88 active.

The power tool sense circuit 70 is provided with a current transformer90 that senses current passing through an electrical connection to thepower outlet 72 that supplies power to a power tool that can be pluggedinto the power outlet 72. The current transformer 90 provides a signalto the microcontroller 64 indicative to the activation state of a powertool plugged into the outlet 72. In response to the power tool sensecircuit 70, the microcontroller 64 can automatically activate the vacuummotor 16 for driving the vacuum source. Thus, when a power tool isplugged into the outlet 72 and is activated by a user, the vacuum motor16 can be activated to assist in vacuuming debris that is created by theuse of the power tool. The microcontroller 64 can delay deactivation ofthe vacuum motor 16 after the power tool is deactivated, to allow forthe vacuum 10 to collect debris for a predetermined period of time afterthe power tool is deactivated.

The water sense circuit 74 includes a pair of water sense probes 96disposed within the canister 12 of the vacuum 10. Probes 96 can beconnected to vacuum head 14 and can be suspended within the canister 12below the level of the filter 26. A buffer device 98 buffers the highimpedance water sense input. The microcontroller on its own isunreliable in measuring the high impedance water sense input. The outputof the buffer device or amplifier 98 goes to an analog input to themicrocontroller 64. The microcontroller software determines the analoglevel to detect water sense. The water sense probes 96 can be brassprobes mounted in the vacuum's canister 12. Water contacting between theprobes will be detected by the water sense circuit 74 as a lowerimpedance.

The electrical isolation circuit 62 is provided to eliminate shockhazard. Three components provide isolation including the power supplytransformer 100 as well as the current transformer 90 and theopto-couplers 82, 86. The power supply transformer 100 provides areduced voltage output from the power source 54. By way of example, afive volt reduced power supply VCC can be provided by the electricalisolation circuit 62 from the AC line voltage source 54. The circuit 60previous to the transformer is the control circuit for the switchingsupply. The transformer provides isolation and is part of the switchingsupply. The five volt regulator takes the isolated control circuitoutput and reduces it to +5V regulated. The low voltage power supply VCCis utilized by the microcontroller 64 for providing signals to theopto-couplers 82, 86 of the filter cleaning circuit 66 and vacuumcircuit 68 as well as supplying power to the water sense circuit 74.Furthermore, the ratio switch circuits 76, 78 are supplied with the lowvoltage VCC power supply.

1. A vacuum comprising: a housing; a vacuum source disposed in saidhousing; a power cord adapted to be connected to an external powersource; an electrical isolation circuit including a power supplytransformer for providing a low power output having a lower voltage thansaid external power source, a controller connected to said electricalisolation circuit for receiving said low power output, said controllerproviding a vacuum control signal to a vacuum circuit for activatingsaid vacuum source, said vacuum circuit being responsive to a low powersignal to provide power from the external power source to said vacuumsource.
 2. The vacuum according to claim 1, wherein said vacuum circuitincludes an opto-coupler for providing power from the external powersource to said vacuum source.
 3. The vacuum according to claim 1,further comprising a vacuum filter disposed upstream of said vacuumsource and a filter cleaning device including a filter cleaning motorand a filter cleaning mechanism drivingly connected to said filtercleaning motor, said controller providing filter cleaning control signalto a filter cleaning circuit for activating said filter cleaning device,said filter cleaning circuit being responsive to a low power signal toprovide power from the external power source to said filter cleaningdevice.
 4. The vacuum according to claim 3, wherein said filter cleaningcircuit includes an opto-coupler for providing power from the externalpower source to said filter cleaning device.
 5. The vacuum according toclaim 1, further comprising a water sense circuit connected to saidelectrical isolation circuit for receiving said low power output, saidwater sense circuit including a pair of water sense probes disposed in adebris chamber of said housing for providing a water sense signal tosaid controller for deactivating said vacuum source when water isdetected by said pair of water sense probes.
 6. The vacuum according toclaim 1, further comprising a power outlet disposed on said housing anda power tool sense circuit connected to said controller for providing asignal indicative of an activation state of a power tool plugged intosaid power outlet, said controller activating said vacuum source inresponse to detected activation of said power tool.
 7. A vacuumcomprising: a housing; a vacuum source disposed in said housing; a powercord adapted to be connected to an external power source; an electricalisolation circuit including a power supply transformer for providing alow power output having a lower voltage than said external power source,a controller connected to said electrical isolation circuit forreceiving said low power output, said controller providing a vacuumcontrol signal to a vacuum circuit for activating said vacuum source,said vacuum circuit being responsive to a low power signal to providepower from the external power source to said vacuum source; and a vacuumfilter disposed upstream of said vacuum source and a filter cleaningdevice including a filter cleaning motor and a filter cleaning mechanismdrivingly connected to said filter cleaning motor, said controllerproviding a filter cleaning control signal to a filter cleaning circuitfor activating said filter cleaning device, said filter cleaning circuitbeing responsive to a low power signal to provide power from theexternal power source to said filter cleaning device.
 8. The vacuumaccording to claim 7, wherein said vacuum circuit includes anopto-coupler for providing power from the external power source to saidvacuum source.
 9. The vacuum according to claim 7, wherein said filtercleaning circuit includes an opto-coupler for providing power from theexternal power source to said filter cleaning device.